21091854457 has 8 divisors (see below), whose sum is σ = 23507949600. Its totient is φ = 18806359104.

The previous prime is 21091854439. The next prime is 21091854521. The reversal of 21091854457 is 75445819012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21091854457 - 2²⁷ = 20957636729 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21091851457) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32649607 + ... + 32650252.

It is an arithmetic number, because the mean of its divisors is an integer number (2938493700).

Almost surely, 2^21091854457 is an apocalyptic number.

It is an amenable number.

21091854457 is a deficient number, since it is larger than the sum of its proper divisors (2416095143).

21091854457 is a wasteful number, since it uses less digits than its factorization.

21091854457 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65299895.

The product of its (nonzero) digits is 403200, while the sum is 46.

The spelling of 21091854457 in words is "twenty-one billion, ninety-one million, eight hundred fifty-four thousand, four hundred fifty-seven".